Laboratory of Intelligent Systems, Institute of Microengineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland.
Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne CH-1015, Switzerland.
Nat Commun. 2017 Feb 17;8:14494. doi: 10.1038/ncomms14494.
To escape danger or catch prey, running vertebrates rely on dynamic gaits with minimal ground contact. By contrast, most insects use a tripod gait that maintains at least three legs on the ground at any given time. One prevailing hypothesis for this difference in fast locomotor strategies is that tripod locomotion allows insects to rapidly navigate three-dimensional terrain. To test this, we computationally discovered fast locomotor gaits for a model based on Drosophila melanogaster. Indeed, the tripod gait emerges to the exclusion of many other possible gaits when optimizing fast upward climbing with leg adhesion. By contrast, novel two-legged bipod gaits are fastest on flat terrain without adhesion in the model and in a hexapod robot. Intriguingly, when adhesive leg structures in real Drosophila are covered, animals exhibit atypical bipod-like leg coordination. We propose that the requirement to climb vertical terrain may drive the prevalence of the tripod gait over faster alternative gaits with minimal ground contact.
为了逃避危险或捕捉猎物，奔跑的脊椎动物依赖于最小地面接触的动态步态。相比之下，大多数昆虫使用一种三足步态，即在任何给定时间至少有三条腿接触地面。对于这种快速运动策略的差异，一个流行的假设是，三足步态允许昆虫快速穿越三维地形。为了验证这一点，我们通过计算为基于黑腹果蝇的模型发现了快速运动步态。事实上，当优化具有腿部附着力的快速向上攀爬时，三足步态会排斥许多其他可能的步态。相比之下，在没有附着力的情况下，新型的两足三足步态在模型中和六足机器人上在平坦地形上是最快的。有趣的是，当真实果蝇中的粘性腿部结构被覆盖时，动物会表现出非典型的类似三足的腿部协调。我们提出，攀爬垂直地形的要求可能导致三足步态比最小地面接触的更快替代步态更为普遍。
